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+ # Alpha 21064 __mpn_lshift --
+
+ # Copyright (C) 1994, 1995 Free Software Foundation, Inc.
+
+ # This file is part of the GNU MP Library.
+
+ # The GNU MP Library is free software; you can redistribute it and/or modify
+ # it under the terms of the GNU Lesser General Public License as published by
+ # the Free Software Foundation; either version 2.1 of the License, or (at your
+ # option) any later version.
+
+ # The GNU MP Library is distributed in the hope that it will be useful, but
+ # WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ # or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
+ # License for more details.
+
+ # You should have received a copy of the GNU Lesser General Public License
+ # along with the GNU MP Library. If not, see <http://www.gnu.org/licenses/>.
+
+
+ # INPUT PARAMETERS
+ # res_ptr r16
+ # s1_ptr r17
+ # size r18
+ # cnt r19
+
+ # This code runs at 4.8 cycles/limb on the 21064. With infinite unrolling,
+ # it would take 4 cycles/limb. It should be possible to get down to 3
+ # cycles/limb since both ldq and stq can be paired with the other used
+ # instructions. But there are many restrictions in the 21064 pipeline that
+ # makes it hard, if not impossible, to get down to 3 cycles/limb:
+
+ # 1. ldq has a 3 cycle delay, srl and sll have a 2 cycle delay.
+ # 2. Only aligned instruction pairs can be paired.
+ # 3. The store buffer or silo might not be able to deal with the bandwidth.
+
+ .set noreorder
+ .set noat
+.text
+ .align 3
+ .globl __mpn_lshift
+ .ent __mpn_lshift
+__mpn_lshift:
+ .frame $30,0,$26,0
+
+ s8addq $18,$17,$17 # make r17 point at end of s1
+ ldq $4,-8($17) # load first limb
+ subq $17,8,$17
+ subq $31,$19,$7
+ s8addq $18,$16,$16 # make r16 point at end of RES
+ subq $18,1,$18
+ and $18,4-1,$20 # number of limbs in first loop
+ srl $4,$7,$0 # compute function result
+
+ beq $20,.L0
+ subq $18,$20,$18
+
+ .align 3
+.Loop0:
+ ldq $3,-8($17)
+ subq $16,8,$16
+ subq $17,8,$17
+ subq $20,1,$20
+ sll $4,$19,$5
+ srl $3,$7,$6
+ bis $3,$3,$4
+ bis $5,$6,$8
+ stq $8,0($16)
+ bne $20,.Loop0
+
+.L0: beq $18,.Lend
+
+ .align 3
+.Loop: ldq $3,-8($17)
+ subq $16,32,$16
+ subq $18,4,$18
+ sll $4,$19,$5
+ srl $3,$7,$6
+
+ ldq $4,-16($17)
+ sll $3,$19,$1
+ bis $5,$6,$8
+ stq $8,24($16)
+ srl $4,$7,$2
+
+ ldq $3,-24($17)
+ sll $4,$19,$5
+ bis $1,$2,$8
+ stq $8,16($16)
+ srl $3,$7,$6
+
+ ldq $4,-32($17)
+ sll $3,$19,$1
+ bis $5,$6,$8
+ stq $8,8($16)
+ srl $4,$7,$2
+
+ subq $17,32,$17
+ bis $1,$2,$8
+ stq $8,0($16)
+
+ bgt $18,.Loop
+
+.Lend: sll $4,$19,$8
+ stq $8,-8($16)
+ ret $31,($26),1
+ .end __mpn_lshift